Introduction

Leucospilapteryx venustella (Clemens) (Lepidoptera: Gracillariidae) is a small, mostly light brown moth that during its larval stages creates mines in the leaves of plants in the family Asteraceae. Feeding damage by the early instars is characterized by serpentine mines that are expanded by later instars to form tentiform or blotch mines.

Figure 1.

Adult resting posture of Leucospilapteryx venustella (Clemens).

Credit:

Photograph by Rodrigo Diaz, University of Florida

[Click thumbnail to enlarge.]

Distribution

Figure 2.

States where Leucospilapteryx venustella (Clemens) has been reported in the United States.

Credit:

Map by Rodrigo Diaz, University of Florida.

[Click thumbnail to enlarge.]

Leucospilapteryx venustella occurs in North America including Canada (Québec) and the United States. In the US, it is found in Wisconsin, Minnesota, Pennsylvania, Kentucky (Opler et al. 2013), Illinois (Harrison and Berenbaum 2012), and Florida (R. Diaz unpublished data) (Fig. 1). The disjunct distribution could be due to inadequate sampling.

Description

Adults

Adults are light brown with a forewing length of approximately 4.2 ± 0.2 mm ( ± indicates the standard deviation in this measurement). The moth’s head is covered by relatively broad, flat, white scales above the eyes and between the antennae. The forewings are patterned in various shades of brown, with 3 to 4 slender, oblique bands (strigulae) of white from the anterior (costal) margin of the wing. The hind margin of the basal half of the forewing is also white (Fig. 2). Adults rest in a 45 degree angle posture (Fig. 3). Figure 4 and 5 illustrate the genitalia of the male and female, respectively.

Eggs

Leucospilapteryx venustella females oviposit a single egg on the underside of leaves. The white, translucent eggs are minuscule with an approximate length of 0.34 ± 0.1 mm (Fig. 6). The chorion of a hatched egg is found at the initiation of the serpentine mine.

Figure 6.

Egg of Leucospilapteryx venustella (Clemens).

Credit:

Esteban Tapia, University of Florida.

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Larvae

The larvae of Leucospilapteryx venustella are hypermetamorphic (Davis 1987), which means that there are two distinct larval body forms, as is characteristic of members of the family Gracillariidae. Early instars are sap-feeders with flattened bodies and their mouthparts directed forward (prognathous) (Fig. 7). Later instars are leaf-feeders with cylindrical bodies and their mouthparts directed downward (Fig. 8). The body length varies from about 2.7 ± 0.2 mm for early instars to about 4.8 ± 0.3 mm for later instars. The feeding damage by early instars can be recognized as a serpentine mine in the leaf (Fig. 9), while later instars form tentiform or blotch mines, which sometimes contain accumulation of frass (Fig. 10). Before exiting a mine, the larva changes color from whitish to deep red (Fig. 11). The last instar stops feeding, exits the mine, and pupates inside a small cocoon in leaf folds. The prepupal instar searches for crevices on the plant or folds over the leaf edge with silk and forms a cocoon (Fig. 12). The length of the prepupa is 4.0 ± 0.3 mm

a) Mikania scandens leaf with tentiform or blotch mines caused by Leucospilapteryx venustella (Clemens) larvae. b) Open mine with larva and plant tissue damage; note the central accumulation of frass made by the larva

Credit:

Rodrigo Diaz, University of Florida.

[Click thumbnail to enlarge.]

Pupa

The pupa is found inside a white cocoon spun by the last instar (Fig. 13). It is light brown and has an approximate length of 3.2 ± 0.2 mm (Fig. 14). Duration of the pupal stage is about 5 to 7 days.

Biology and Host Plants

Little is known about the biology of Leucospilapteryx venustella. Adults have been associated with plant species in the family Asteraceae. In Illinois, adults have been collected in prairies from June to September using ultraviolet light (Harrison and Berenbaum 2013). Larvae have been reared from the climbing hemp vine, Mikania scandens (L.) Willd (R. Diaz

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U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.